Signal identification marker



FIG. 1 is a perspective view of a signal identification marker;

FIG. 2 is a second perspective view thereof;

FIG. 3 is a top elevational view thereof;

FIG. 4 is a front plan view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a back plan view thereof; and,

FIG. 7 is a bottom elevational view thereof.

The broken line showing of a door is included for the purpose of illustrating portions of the “article” and forms no part of the claimed design. 

CLAIM The ornamental design for a signal identification marker, as shown and described. 